1. Field of the Invention
The present invention relates to novel pseudo cross-link type polymer molecules and resin compositions made of mixtures of these polymer molecules.
2. Description of the Related Art
Recently, researches and developments of synthetic resins have accomplished great advances, and synthetic resins having various performances have been obtained. Among such researches and developments, there are many approaches that, without damaging resins' intrinsic performances, intend to endow existing synthetic resins with new performances.
As a typical synthetic polymer molecule material, acrylic resin or styrenic resin can be cited. These synthetic resins have various excellent characteristics such that these resins are relatively cheap, superior in transparency, can be relatively easily manufactured into polymers having various characteristics from rubber-like materials to glass-like polymers, and can be easily modified. On the other hand, there remain large problems in compatibility between mechanical strength, heat resistance and toughness, and improvement thereof. The deficiency of the toughness is a problem common to an entirety of acrylic resins. Accordingly, there are several reports that teach how to overcome these problems. For instance, it is known to mix rubber particles in a resin (Japanese Patent Application Publication Nos. 58-167605 and 3-52910). However, these methods cannot overcome a blushing phenomenon that occurs when a resin is folded (folding property). At present, an acrylic resin that can combine a glass transition point that is equal to or more than room temperature and an ability to form a tough thin film (folding property) has not been found.
Furthermore, as a typical aromatic polyamide resin, polyparaphenylene terephthalamide can be cited. It has particularly excellent crystallinity, a higher melting point and excellent flame resistance, and furthermore owing to a rigid molecular structure, a higher mechanical strength, a lower linear expansion coefficient and so on. However, there is a problem in that it is very difficult to dissolve in an organic solvent, accordingly an inorganic strong acid such as concentrated sulfuric acid or the like has to be used as a solvent. It is known that fibers spun from a thick solution of such as concentrated sulfuric acid or the like have very high mechanical strength and elasticity, and are industrially put into practical use. However, applications into films are hardly found, and in one example it is reported that only a swollen state allows to be drawn (Japanese Patent Application Laid-Open No. 4-6738). In the method, there are problems in that since a manufacturing process is extremely complicated, productivity is lowered, and product prices become higher. As a method that allows improving the solubility in organic solvents, it is known that when monomers in which a halogen group is introduced in an aromatic nucleus or monomers high in flexibility are copolymerized, its solubility into organic solvents can be improved (Japanese Patent Application Publication No. 56-45421). However, in this method, since the price of the monomer becomes higher, product prices become higher, higher heat resistance and flame resistance may be damaged, and in addition to the above, there is a problem in that halogen atoms may cause metal corrosion.
A liquid crystalline polymer, in order to exhibit a liquid crystal state in a molten state, has higher elasticity and mechanical strength, and furthermore a lower linear expansion coefficient in an orientation direction. However, as common problems to the liquid crystal polymers, there are disadvantages such that the aforementioned performances are extremely lower in a vertical direction to the orientation direction, mechanical strength at a meeting point of a molten resin that is generated when a molded body is obtained by use of injection molding and called as weld is extremely low, and furthermore a surface of the molded body is peeled in layers. However, at present, solutions of the problems are not known.
A polymer alloy material, which aims to obtain a new performance by mixing different kinds of polymer molecule materials, has been prepared by mixing polymer molecules different in affinity by help of a compatibility agent. Since the method is a technology that aims to reduce a surface energy by use of the compatibility agent, it can control a dispersion state that causes an island structure but cannot attain a completely compatible state. There have been no reports in which different kinds of polymer molecules are made completely compatible. In addition, there are problems in that since the compatibility agent is relatively expensive, the product prices become higher; when the polymer alloy material is used for long, the compatibility agent breeds out on a surface and thereby contamination is caused; and the dispersion state of the polymer alloy material may change.
Since thermosetting resins are generally insoluble and infusible cured-materials, these are particularly excellent in solvent resistance or durability such as strength maintenance rate or the like under high temperatures. However, since cross-links are formed through covalent bonds, there is a problem in that the thermosetting resins cannot be reproduced. Accordingly, there is a big disadvantage in securing recycle properties thereof. As one that is most close to thermosetting resins that can be recycled, ionomer resins can be cited. In the ionomer resin, a metal oxide or metal hydroxide such as magnesium oxide or calcium hydroxide is added to a polymer having a carboxyl group in its side chain. By forming an ionic bond between the metal and the carboxyl group, a pseudo cross-link point is formed. In the method, although a certain degree of improvement in heat resistance and toughness can be obtained, according to reasons such that a bonding force between the metal compound and the carboxyl group is weak, owing to lower solubility of the metal compound in the resin only a slight amount can be added, and so on, a larger improvement in characteristics cannot be obtained.
Furthermore, among the thermosetting resins polyimide resins have extremely high heat resistance and tough film performance, accordingly are industrially extremely useful materials. When processing polyimide into a film, in general a polyimide solution is coated, followed by heating at a high temperature, and thereby an imide ring is formed. In addition, when the imide ring is once formed, solubility in a solvent is extremely lowered. This becomes a disadvantage when the polyimide is recycled. Accordingly, materials that can combine high solubility in a solvent and high heat resistance are in demand. A method is known in which by copolymerizing monomers in which a substituent group such as an alkyl group or the like is introduced in an aromatic nucleus, the solubility in an organic solvent is improved. However, by the method, materials having a glass transition temperature equal to or more than 320° C. have not been obtained. Furthermore, in the method, since monomer price is expensive, there is a problem in that the product price becomes higher.
Accordingly, polymer molecules that can be easily polymer mixed, can exhibit a new performance, and thereby enables to combine in particular contrary characteristics or resin compositions made of mixtures thereof are in demand.